Rotary machines typically utilize vane motors that are pneumatically powered to cause rotation of the output shaft. As is well known these machines comprise a cylinder, sometimes referred to as a casing and an eccentrically mounted spindle in the cylinder, sometimes referred to as a rotor. The cylinder is stationary and through apertures in the cylinder lead pressurized air to impinge on the reciprocating vanes mounted in slots formed in the spindle to cause the spindle to rotate and exhaust the spent air through additional holes formed in the cylinder. The outer edge of the vanes is in contact with or in close proximity to the inner surface of the cylinder during the power stroke of the vane motor and during the exhaust portion of the stroke the spindle recedes from the inner surface of the cylinder. Heretofore the vanes have been a rectangularly shaped planar member with a top and bottom straight edge where the bottom edge fits into slots formed in the spindle and the top straight edge bears against or is in close proximity to the circular surface of the cylinder. During the power stroke the vanes are in position adjacent to the inlet apertures. The slots in the vanes for supporting the vanes typically are oriented to be in coincidence with the center line of spindle. Obviously, the rotational speed is dictated by the power stroke, the pressure of the pressurized air and the area of the vane/spindle where the air impinges thereon.
I have found that the vane motor can be enhanced by undercutting the slots supporting the vane, by providing slots at judicious locations formed in the spindle, and/or by orienting the axial vane slots so that they are displaced from the centerline of the spindle. Adding slots to the spindle adds additional working area and undercutting the slots supporting the reciprocating vanes increases the working area of the vanes. In other words, a vane motor designed with the above features provide for a given pressure of the pressurized air, a vane motor that will rotate faster and produce more torque. Or, otherwise, the vane motor can be made smaller while producing the same rpm and torque that would be produced by a larger sized vane motor.